Lock fob bastes



NUnire srarns PATENT Erica.

A JOHN OXNARD, OF PORTLAND, MAINE.

LOCK FOR BANKS, VULTS, SAFES, &C.

Specification of Letters Patent No. 3,990, dated April 10, 1845.

tumblers and other operative parts therein,`

the cover or movable plate of the lock case being supposed removed inorder to clearly exhibit them. Fig. 2, is a transverse section of thelock taken centrally through the tumblers.

Such other figures or drawings as may be necessary to the descriptionhereinafter given will be therein referred to and described.

The lock case (A, Figs. 1, 2), isa rectangular or other proper shapedbox ofnietal, whose top plate (represented in Fig. 5) is removed from itfor the purpose hereinbefore set forth. In the said lock case, a bolt(B) and series (C) of sliding tumblers or plates, such as usuallyemployed in bank locl s,`are disposed with respect to each other as seenin Figs. l, 2. Instead of raising the said tumblers, by a lieyconstructed in the usual manner, I employ a circular, or other propershaped piece of metal (1),) which is placed immediately below thetumblers and supported in such manner in bearings in or applied to thelock case, as to revolve on its aXis or center E. The said piece ofmetal, is to be moved or caused to turn upon its center, by a simplekey, which is to be made to tit upon a square stud, projecting from thecentral part of said circular piece of metal, as seen at, a, Figs. 1, 2,-3 and 4. The said piece of metal (D) has a rectangular or elongatedorifice formed tliro-ugh it (as seen at F,) into which a bit plate ofmetal (G) is to be inserted and so adapted thereto, I

as to be placed therein and removed therefrom at pleasure. A side viewof the circular block (D), is given in Fig. 3, and a front elevation ofit in Fig. t. A portion of its lower part on each side of the bit plateis removed as seen in the drawings, the remaining portion of the saidlower part, (which is represent-ed at Z) in Figs. 3 and 4f)constituting, as it were, a tianch or projection', which receives, andin part sustains the bit plate G. )Vhen the cover of the lock, (see Fig.5) is applied to, or inserted in, its placeA within the case, a smallelongated orilice (c) in it, of a size large enough to permit thepassage through it of the bit plate, should come just over andcorrespond with, the hole or passage F, in order that the bit plate maybe readily inserted in, 0r withdrawn from, the revolving block D, as

`occasion may require. The tumblers are to `play within, or between sidepartitions H,

H, which should extend down to the block D, and may continue partiallyaround it, if desirable,

The bit plate G (a side View of which as detached from the block D, isgiven in Fig. 6, wherein it will be seen that it resembles the bits of acommon key) being inserted in the revolving block D, on turning the saidblock, the said bit plate will be carried around by it, so as to be`brought beneath, and in contact with the sliding tumblers, and iii suchmanner as to act on them, as a key usually does, or will elevate them tothe positions required for the movement of the bolt stud (d) through thehorizontal passage (e) of each of the sliding tumblers and then 4meets apin or catch z' on the end of a small spring lever I (which is jointedat one end to the lower part of the bolt and has a spring (72,) appliedto it on the bolt, and acting upon it in such manner, as. to force itdownwarch) against which it acts, so as to force or throw the boltforward. On reversing the movement of the block D, so as to carry thebit plate around in contact with the front side of said pin or catch z',(extending from the spring lever I) and continuing the movement of theblock D, the bolt is thrown back within 'the case-or, in commonparlance, is unlocked.

From the above, it will be seen, that a very slight movement of therevolving block, either to the right or left, completely closes up anypassage into the lock, through what may be tern'ied the key hole thusrendering it either impossible or extremely diiiicult for a pick lock toinsert any instrument into the lock, or obtain such access to the tumiblers and other parts, as may be required to pick it. The bit plate mayhave a small staple, fitted in its upper edge, through which, (staple) ahook may be passed, in order to remove it from the lock, or insteadthereof, any other suitable mechanical device may be resorted to, inorder to effect the same object.

It is well known, that the mode generally adopted in order to pick locksof this description, (that is, those having moving tumblers connectedwith the main bolt) ,has been to insert some instrument through the keyhole, and into the lock, and by the same to act upon the bolt, in suchmanner as to press or force it back, so that its stud which projectsthrough the tumblers, shall be borne against the rear sides of each ofthe front vertical slots of the series of tumblers. This done, somemeans are next resorted to, whereby th-e levers may be successively andcarefully elevated, to the height necessary to allow of the passage ofthe bolt stud through the horizontal slots, of the tumblers, and intothe rear vertical slot. The back pressurey of the bolt is relied upon,to keep each tumbler at the proper elevation when raised thereto.

By examining my improved lock it will be seen, that the only chance apicklock has to operate on the tumblers, when the bit plate G, isremoved from the revolving block D, is to insert some instrument in theblock D, in the place of the said bit plate. We will suppose, for thesake of illustra` tion, that he has by some means raised one of thetumblers to the height required. This being effected, the next operationto be performed by him, is to turn the block D, back to the position,which will enable him to insert a bit or some other instrument in theblock, by which he can operate on some one of the tumblers. Generallyspeaking, the removal of the force from the bolt by which it is pressedback, as before described, would so relieve the raised tumbler from thepressure of the bolt stud, as to allow the weight of the tumbler tocause it to descend. The weight and friction of the bolt, however, mayprevent this, and, therefore, in o-rder to insure the fall of thetumbler I apply a contrivance to the bolt, which will throw it forward,or overcome its inertia, at the moment the block D, is moved for thepurpose above named. The said contrivance consists of a lever 7s, (seeFig. 1,) which turns upon a pin or fulcrum at one end or at Z, and isplaced with respect to the bolt as seen in the drawing. It is forcedagainst the lower side of the bolt, by a spring m, and when the bolt isthrown forward its (the levers) upper end u, is thrown upward, int-o acurved cam notch 0, eut in the lower edge of the bolt, as seen in Fig.l. rlhe said notch is to be so formed, that whenever pressure is appliedto the bolt, in order to throw it back and cause its stud to bearagainst the rear sides of the front Vertical slots of the tumblers, theinclined front side of the notch o, will slightly de` press the end ofthe lever in contact with it. On removal from the bolt, of the force, bywhich it is thrown back, the pressure of the spring lever 7c, againstthe inclined front side of the notch 0, will throw the bolt forpf'a'd,so as to permit the raised tumbler to Having, therefore, described myimprove- JOHN OXNARD. Witnesses:

EDWARD FOX, THOMAS SEAL.

